The invention is in the field of magnetotorquers particularly suitable for use in earth orbiting satellites for steering and stabilization purposes.
A magnetotorquer hereinafter referred to a xe2x80x9cMTQxe2x80x9d has a ferromagnetic core with an excitation coil wound therealong through which a current passes for generating a total magnetic dipole M for imparting a torque T given by the vector product of {overscore (T)}={overscore (M)}xc3x97{overscore (B)}earth.
The total magnetic dipole M is derived as follows:   M  =                    1                  μ          0                    ⁢                        ∫          v                ⁢        BdV              ≈          μ      ·      n      ·      I      ·      V      
where xcexc0 is the permeability of free space, B is the local flux density, xcexc is the effective permeability, n-I is defined as the excitation force and is the product of the number of windings per total core length n and the excitation current I, and V is the core""s volume.
A convention MTQ has a right cylindrical core with an excitation coil uniformly wound therealong and whose distribution of the total magnetic flux xcfx86 therealong is characterized by a maximum flux density value at its core""s center and a flux density value of less than 2% of the maximum value at its core""s ends.
In accordance with a first aspect of the present invention, there is provided a magnetotorquer comprising a ferromagnetic core with an excitation coil more compacted at its central portion than at at least one of its lateral portions.
Compacting the MTQ""s excitation coil at its central portion increases the local flux density thereat in comparison to a conventional MTQ assuming the same excitation force. The advantage afforded thereby is that the same total magnetic dipole can be obtained with a smaller excitation force effected by either a smaller current consuming less power or less windings which weigh less.
In accordance with a second aspect of the present invention, there is provided a magnetotorquer comprising a ferromagnetic core with an excitation coil wound therealong, said core having a central portion intermediate to lateral portions, at least one lateral portion having a smaller material cross section area than said central portion.
Reducing the material cross section area of preferably both of a core""s lateral portions has the effect of increasing the local flux density thereat in comparison to a conventional MTQ assuming the same excitation coil and excitation force without, however, reducing its total magnetic dipole. The advantage afforded thereby is that material can be removed from the core thereby reducing its overall weight.